It depends when your horses are having babies
4
The great Seabiscuit sired many foals, none even came close to him as a racer.
It appears that Aristides only sired four foals, all of which were fillies.
Man o' War sired 386 registered foals.
zero.
As many as you want there to be! (sigh)
10 to 15
100
Foals lbs 100
He sired 654 foals.
Newborn foals average 125 pounds
Rider at the Gate has 437 pages.